The present invention generally relates to a computer system configured from a computer and a storage system, and in particular relates to a method of migrating data and history information to be updated by the computer between storage systems.
There is technology for storing update history of data and restoring data of an arbitrary time in data update (write) units. Japanese Patent Laid-Open Publication No. 2005-18738 (Patent Document 1) discloses technology of managing update history information (journal) of data in the same cabinet enclosure, and restoring data at an arbitrary point in time within a recoverable range. With the technology disclosed in Patent Document 1, if the storage extent for storing the update history information of data runs short, the storage extent is secured by deleting the update data at a point in time in order from the oldest update history or reflecting the update data to the data at such point in time so as to store the newly updated data of the update history information.
Further, US20050028022A1 (Patent Document 2) discloses technology of increasing free space by compressing and reducing the size of the update data in the event that the storage extent for storing the update history information of data runs short. Nevertheless, even with the technology disclosed in Patent Document 2, if the storage extent still runs short after the compression, it is necessary to delete the update data at a point in time in order from the oldest update history or reflect the update data to the data at such point in time.